Rack



April Si," 14930- J. c. DRADER 1,753,778

RACK

Aoriginal Filed Nov. 10,.,.12v

A TTORNEY Patented Apr. 8, 1930 UNITED s'rAras i PATENT oar-ics Iosnrn c. Danna, or DETROIT, moment RACK Original application illed November 10, 1927, Serial No. 232,226. Divided and this applicativa: illed June- 19, 1929. Serial No. 372,172. f'

. v'This invention relates to toothed racks for engagement by gears or the like, the principal object being the provision of avery accurate rack construction, and is a division of i i means effective upon all of a row of members my application for Letters Patent of the United States on lead testing'machine, Iiled November 10, 1927, Serial No. 232,226.,

Another object of the invention isto permit the Yteeth of a rack to be very accurately,

spaced in proper coacting relation by forming said teeth upon separate members and selectively positioning said members with respect to one another to compensate for any variations in the thickness of said members.

Another object is to provide a clamping individually forming rack teeth, to permanently maintain said members in proper coacting relation.

A further object is to form rack teeth upon correspondingends of a plurality-of members adapted to be secured in abutting relation, and to so bevel corresponding side edges of said members as to adapt them'to be firmly clamped upon a suitable support by an element extending longitudinally of the rack in engagement with said beveled faces.

These and various other objects the invention attains by the construction hereinafter described and illustrated in the accompany- Y ing drawings,l wherein Fig. -1 is a plan view of the improved rack.

Fig. 2 is a cross sectional view of the same, taken upon the line 2- -2 of Fig.'1, and drawn to alarger scale.

Fig. 3 is a fragmentary vertical section taken longitudinall of the rack through an end portion thereo as'indicated by the line 3-3 of Fig. 2, and'drawn to a larger scale.

' In these views, the reference character 1 designates a portion of the machine or apparatus of which the rack forms a part, and 2 i indicates the basel of the rack which has preferably the nature of arf elongated metallic bar, secured to the support 1 by a plurality of' cap screws 3 or the like. The base 2 is formed with a channel 4 opening in its top face and extending lengthwise of the base i-n a preferably equidistant relation to the sides thereof. In the channel is disposed fa row of toothforming members 5 having their abutting faces preferablyparallel, and having their upper ends formed as teeth which project above said base, as best appears in Fig. 3. It is preferredto form these members of tool steel of uniform thickness.

I The members 5 are seated upon a liner strip 6 engaging the bottom of the channel 4, and rigidly secured to the base 2 by screws 7. A similar liner strip 8, perpendicular to the liner strip 6, engages a side wall of the channel and is rigidly secured thereto by screws 9. The side edges of the members 5 engaging the liner 8 are transverse to the length of the teeth, and their opposite side edges are slightly inclined to the length of the teeth, as indicated at 10, so as to gradually increase the width of the members 5 as they extend from their toothed edges toward their base.

The inclined edges 10 are engaged by a wedge 11 having its inner face beveled correspondingly to the edges l0 of the -members 5, and fitted between said members and the adjacent side wall of the channel 4.- At its bottom, the wedge is spaced above the bottom ends of the members 5 so that it may be forced downwardly between said members and the adjacent channel side wall to firmly clamp the members 5 against the liners 8 and 16. To apply the 'clamping stresses, a plurality of screws-12 are tapped into the top face of the base, with their heads bearing upon 'l shoulders 13 formed by recessing the sides of ,the wedge. Itis to be particularly noted .the corresponding end members 5, and their opposite faces are slightly inclined, as indiv cated at 15. The faces engage correspondingly inclined faces formed upon abutment blocks 16 which extend across the rack chani nel and are snuglytted into grooves 17, transversely formed in the base at its oppo-V curately position the wedges 1li-with respect vposition said blocks.

to the sides ofthe base 2 by forming the wedge-engaging faces of said blocks with shallow grooves 18 to receive said wedges, and the opposite faces of said blocks are formed with projections 19 fitting into the channel 4 toward the baseextremities, to additionally For applying a clamping stress to the wedges 14, screws 20 are downwardly ext-ended through suitable bores in said wedges and tapped into the base 1.

By forming the rack teeth individually upon separate members and assembling said members in the described manner, it is possible to secure substantially perfect uniformity of spacing between said teeth. It may appear that errors arising from any slight varia-' tions in the thickness of the members 5 will be accumulative in their eiect, but a complete compensation for any such errors is possible by so relatively .positioning said members prior to permanently clamping them in place, as to secure the desired uniformspacing of the teeth.

It is an important feature of the constructionthat the tooth-forming members have abutting portions considerably larger than the teeth thereof, so as to provide bearing faces of considera-ble size, the clamping engagement of which will accurately main ain the teeth in the desired relation.

rI`he described rack has a particular application to use in machines for testing the lead of screw threads, spiral gears, or other helically-shaped parts, but may further be employed wherever it is important to secure a high degree of accuracy as'y regards the spaced relation of rack teeth.

, lNhat I claim is:

'1. A toothed rack comprising a row of abutting members having corresponding edge portions thereof spaced and fashioned to form rack teeth, and means forF applying a clamping stress to all of said members through an application of pressure to the end members of the row.

2. A toothed rack'comprising a row of Vabutting members lhaving corresponding edge portions thereof spaced and fashioned to form rack teeth, a base carrying said members, an abutment upon said base,V for one end of the row, a wedge member engaging the other end of the row, and a screw` engaging said wedge member with said base to clamp -saidrow against said abutment.

3. A toothed rack comprising a supporting base formed with a longitudinal channel, a plurality of tooth-forming members formin a row in said channel, means carried by sai base for exerting a clamping pressure upon said members lenglthwise ofthe row, and means carried by t e base for clamping said members against a side wall and a bottom wall of said channel.

4. A toothed rack comprisin a supporting base formed with a channel, a utments carried by said base at the ends of said channel, a row of tooth-forming members arranged in said channel between said abutments, a wedge entered in said channel between said row and one of said abutments, and means ,engaging said `wedge with said base for actuating the wedge forcibly into the channel.

5. A toothed rack comprising a channeled base, a plurality of members arran ed within the channel of the base and'having aces abutting transversal to the length of the channel, said members eing formed with coacting rack teeth projecting above said base in spaced relation, and means carried by the base for rigidly securing said toothed members in' their abutting relation.

6. A toothed rack comprising a plurality of separately formed members arran ed in a row in abuttin relation and forme upon corresponding e ges with spaced rack teeth, and correspondingly tapered in width from their toothed edges to their opposite ends, and means cooperating with corresponding side edges of said teeth for rigidly/securing sai teeth in the described relation.

7. A toothed.rack comprising a row of members formed upon corresponding vedges with spaced rack teeth, of a base mounting said members, providing a seat for corresponding side edges thereof, a wedge member engaging the opposite side edges of said teeth, a member carried by the base for guiding the wedge member in its Wedgingl travel, and

means carried by the base for actuating such 8. In combination, a supporting `member provided with a groove, a plurality of separately formed rack teeth positioned in said groove and projecting therefrom, each of said teeth increasing in width from the top thereof to its base, and wedging means cooperating with the edges of said teeth for forcing said teeth against .the opposite side and the bottom of'said groove.

9. In combinatiom'a su porting member.

each other.

JOSEPH C. DRADER. 

